On the causality between affective impact and coordinated human-robot reactions

TL;DR

This study explores how the timing and sharing of reactions by social robots influence human perception of their affective impact, revealing optimal reaction delays for enhancing social interaction effectiveness.

Contribution

It introduces experimental methods to isolate and analyze the effect of robot reactions and timing delays on human perception in social contexts.

Findings

Shared reactions significantly increase perceived affective impact.

Optimal reaction delay around 200ms enhances perception for small robots.

Shorter delays (~100ms) maximize human impact perception.

Abstract

In an effort to improve how robots function in social contexts, this paper investigates if a robot that actively shares a reaction to an event with a human alters how the human perceives the robot's affective impact. To verify this, we created two different test setups. One to highlight and isolate the reaction element of affective robot expressions, and one to investigate the effects of applying specific timing delays to a robot reacting to a physical encounter with a human. The first test was conducted with two different groups (n=84) of human observers, a test group and a control group both interacting with the robot. The second test was performed with 110 participants using increasingly longer reaction delays for the robot with every ten participants. The results show a statistically significant change (p$<$.05) in perceived affective impact for the robots when they react to an event shared with a human observer rather than reacting at random. The result also shows for shared physical interaction, the near-human reaction times from the robot are most appropriate for the scenario. The paper concludes that a delay time around 200ms may render the biggest impact on human observers for small-sized non-humanoid robots. It further concludes that a slightly shorter reaction time around 100ms is most effective when the goal is to make the human observers feel they made the biggest impact on the robot.